Process for the closure of hollow bodies



J1me 1964 A. JEAN-BAPTISTE GHISLAIN PICKART 3,136,052

PROCESS FOR THE CLOSURE OF HOLLOW BODIES Filed May 21, 1959 UnitedStates Patent 3,136,052 PROfIESS FOR TIE CLOSURE OF HOLLOW BODIESAuguste Jean-Baptiste Gliislain Pickart, Seraing, Belgium, assiguor toFabrique Nationale dArmes de Guerre, Societe Anonyme, Herstal-lez-Liege,Belgium Filed May 21, 1959, Ser. No. 814,714 Claims priority,application Belgium June 4, 1958 2 Claims. (Cl. 29-543) It is known toeffect the closure of cartridge cases for sporting firearms in variousmanners and particularly by providing folds at the end thereof andturning the folds down towards the centre.

In a conventional process of this nature, the foldingdown is effecteduntil the inner folds project below the plane of the closure, i.e. areinscribed within an extremely obtuse cone towards the interior of thecase. In another process, the folds form projecting ribs externally ofthe plane of closure, inscribed in a truncated cone towards the exteriorof the case.

Since therefore the known processes of closure by folding do not permitthe obtaining of a closure other than a plane or frusto-conical closure,they are not suitable for the manufacture of practice cartridgessuitable for use in all kinds of automatic firearms without any form ofadaptation other than the addition at the end of the barrel of a devicethe purpose of which it is to limit the gas-flow section. In fact, theclosure obtained by these known processes results in the formation of anexcessively large plane surface or of a series of sharp ridgesdistributed over an excessively large diameter which become caught atone or the other point during the travel of the cartridge before it isreceived in the barrel chamber, the result being failure in the feed. Ifit is to function correctly in all cases, the cartridge should terminatein a portion the shape of which is as similar as possible to that of thereal projectile and which guides the cartridge over the path from themagazine to the barrel chamber and its centre of gravity should beconveniently situated in such manner that at the moment of ejection itcarries out the same movements as those of the case of a real cartridge.

Hitherto, during practice, use has been made of ammu nition called blankammunition wherein the projectile is a dummy and consists for example ofa piece of wood having the shape of the real projectile and beinginserted in the case. Although ammunition of this kind is similar toreal ammunition, it has disadvantages during firing practice in whichthe adversaries may fire point-blank since, in this case, the dummybullet is fired like a projectile and may cause accidents.

Practice cartridges are also known wherein the body of the'case ofplastic material is prolonged by a portion in the form of a dummyprojectile which is also of plastic material. The behaviour of thesecartridges, the dummy projectile of which remains integral with thecase, differs from that of real cartridges, in view of the difference inthe nature of the materials; since the specific weights, coefiicients ofexpansion, softening temperatures and mechanical rigidities aredifferent, these cartridges are not entirely satisfactory.

The present invention relates to a process for the closure of hollowcylindrical bodies of slight thickness and consists in forming on theend of the body a small number of folds, in rounding the ridges of theexternal folds whilst simultaneously bending them down towards thelongitudinal axis, and in simultaneously elongating them transversely soas to constitute an ogive (conical point).

According to a feature of the invention, there are initially produced,in a first phase, internal folds which are brought into contact andwhich have substantially the shape of arcs of a circle; the second phaseconsists in flattening the ridges of the external folds whilst foldingthem down towards the axis and elongating them transversely by means ofa concave ogival matrix exerting a longitudinal thrust towards the body,so that each initial external fold yields two lateral folds.

An especially advantageous embodiment consists of practice ammunitionwherein the case is prolonged by an inseparable terminal portioncorresponding to the projectile and having its free end closed by thepresent process; the said cylindrical terminal portion is directlymanufactured with the body of the case and is fitted thereon and securedthereto by welding during the manufacturing process.

Further features will be apparent from the following description of theaccompanying drawings which refer to an embodiment of a practicecartridge.

In the said drawings:

FIGURE 1 is a view, partially in perspective and drawn to a large scale,of the end of a practice cartridge to be closed, shown after the firstphase of operation;

FIGURE 2 is a lateral view, drawn to a large scale and in elevation, ofthe final ogive obtained, and FIG- URE 3 is a sectional view taken alongthe line IIIIII of FIGURE 2;

FIGURE 4 is a diagrammatic view, drawn to a still larger scale, andshowing in plan the end of the ogive and the deformation of the foldsfor forming the ogive;

FIGURE 5 is an elevational view of a completed practice cartridge.

Referring to FIGURE 1, it will be seen that the body 1 of the case isprolonged by a tubular and cylindrical terminal portion 2, the saidportion 2 comes, together with the body 1, directly from the factory inthe case of small-bore ammunition. If the ammunition is of large size,the body of the case and the terminal tubular portion may bemanufactured separately, the said terminal tubular portion then beingmade integral with the case by Welding.

Applied on the circular end of the element 2 is a matrix the interior ofwhich is provided with three pins arranged at under the pressure exertedby the matrix, the end is deformed and is formed with three inner folds3, arranged at 120 relatively to one another, and with three outer folds4 arranged also at 120, as apparent from FIGURES 1 and 4. It should benoted that the inner folds 3 have the form of arcs of a circle broughtinto contact with each other.

In the following phase, the end thus folded is covered with a matrix ofogival shape, exerting an axial thrust towards the body of the case.

By this action, the inner folds 3 substantially retain their shape; atthe beginning of this phase, the initial external folds 4 are flattenedso as to adopt the position 4' shown in broken lines, whilst beingturned down towards the axis 5, as shown in FIGURE 4. The initial folds4 are then crushed (flattened) and laterally extended so as to form thefinal lateral folds such as those shown at 4a and the lips 4b and 4c ofwhich are pressed together; at the point 6 of the ogive, the outer lips4b constitute a more or less complete circular surface (FIGURE 4) sincethe lateral folds 4a are in contact with each other at that point. Thefurther away from the point 6, the greater will be the spacing betweenthe folds 4a, as apparent from FIGURES 2 and 3.

The completed ammunition will have the appearance shown in FIGURE 5.

The process just described permits the obtaining of a practicallycontinuous annular closure surface; the interstices of communicationtowards the interior are almost completely closed and the radius of theclosureogive may be varied in accordance with necessity.

indented sufficiently to cause the internal folds to con- In the case ofpractice ammunition, the terminalportion representing the dummyprojectile is no longer separated from the case; it is not projected andcannot result in accident during point-blank firing; furthermore, theshape and mechanical characteristics of the cartridge resemble those ofa real cartridge as closely as possible.

The description given hereinabove and the drawings relate to a mode ofclosure wherein three folds are used. This number of folds is notlimitative since, where required, use may be made of a larger number offolds;

Calculation shows, however, that there is little advantage in increasingthe number 'of folds with a view to reducing the diameter of theterminal portion. The utilisation of three folds constitutes furthermorea special feature of this mode of closure.

Since the powder charge of a practice cartridge manufactured inaccordance with the present process is diminished, it is necessary tomaintain it in place near the percussion cap by using an adequatetamping means.

tact one another at the end of the body around the longitudinal axis ofsaid body, and deforming the external folds by pressing said externalfolds inwardly in a radial; direction while simultaneously crushing androunding the folds circumferentially into arcuate segments substantiallyof double thicknesscooperatively contacting one another to define asubstantially circular externalsurface,

said crushing androunding of the external folds being" variedlengthwise. of the body to cause the arcuate segments to contactoneanother at the end of the body and to be spaced from'one another in.increasing mannerin a direction away from the end of the body'to form aclosedogival end on said body.

2. A process as claimed in claim 1 wherein thereis'h formed threeexternal and three internal 'folds whereby The said tamping meansconsists of nitrated paper or of some other substance the combustion ofwhich is practically instantaneous, so as to avoid any projection ofsolid fragment out of the barre1, since such projection could entail acertain element of danger.

What I claim is:

1. A method for closing the end'of a hollow cylin drical body comprisingindenting the body radially inwardly at the end thereof at angularlyspaced locations to form arcuate internal folds alternating withexternal" folds along the periphery of the body, the body being adjacentinternal folds includean angle therebetween of 7 R eferenc eslCitedinthe file of this patent UNITED. STATES PATENTS Salisbury June 127,- 1386

1. A METHOD FOR CLOSING THE END OF A HOLLOW CYLINDRICAL BODY COMPRISINGINDENTING THE BODY RADIALLY INWARDLY AT THE END THEREOF AT ANGULARLYSPACED LOCATIONS TO FORM ARCUATE INTERNAL FOLDS ALTERNATING WITHEXTERNAL FOLDS ALONG THE PERIPHERY OF THE BODY, THE BODY BEING INDENTEDSUFFICIENTLY TO CAUSE THE INTERNAL FOLDS TO CONTACT ONE ANOTHER AT THEEND OF THE BODY AROUND THE LONGITUDINAL AXIS OF SAID BODY, AND DEFORMINGTHE EXTERNAL FOLDS BY PRESSING SAID EXTERNAL FOLDS INWARDLY IN A RADIALDIRECTION WHILE SIMULANEOUSLY CRUSHING AND ROUNDING THE FOLDSCIRCUMFERENTIALLY INTO ARCUATE SEGMENTS SUBSTANTIALLY OF DOUBLETHICKNESS COOPERATIVELY CONTACTING ONE ANOTHER TO DEFINE A SUBSTANTIALLYCIRCULAR EXTERNAL SURFACE, SAID CRUSHING AND ROUNDING OF THE EXTERNALFOLDS BEING VARIED LENGTHWISE OF THE BODY TO CAUSE THE ARCUATE SEGMENTSTO CONTACT ONE ANOTHER AT THE END OF THE BODY AND TO BE SPACED FROM ONEANOTHER IN INCREASING MANNER IN A DIRECTION AWAY FROM THE END OF THEBODY TO FORM A CLOSED OGIVAL END ON SAID BODY.